User manual

ZEUS user manual

Issue E

Power and power management

Power supplies

The ZEUS is designed to operate from a single +5V±5% (4.75V to +5.25V) input or the

onboard 10V to 30V DC/DC PSU.

DC input voltage (10-30V)

DC input voltage (10-30V) is connected through a front panel locking DC jack J3 (see the

section J3 – Power connector (10-30V)

, page 70). When operating from the 10 to 30V

input, the 5V connector (J2) is NOT fitted. The input rails are protected from overcurrent,

overvoltage, undervoltage and reverse battery conditions, and include transient

suppression to achieve compatibility with vehicle power supplies. The on-board DC/DC

converter can provide a maximum current of 5A at 5V at a temperature range of 0-70°C

(32-158°F).

For vehicle-based applications, the supervisory circuit monitors the auxiliary ignition

supply input (Vig), and provides feedback of ignition status to the PXA270 (IG_FAIL

signal at GPIO115). If the Vig falls below 9.2V, IG_FAIL becomes logic ‘1’. This can be

used to instigate an orderly shutdown or to store ignition status data.

5V only operation

For 5V only operation, the ATX style connector J2 is used as the main power input for the

ZEUS. In this case, connector J3 and the entire DC/DC PSU circuit is depopulated. The

power connector J2 has a +12V connection too, but it is not required for the ZEUS under

normal operation. It can be used to supply +12V to the PC/104 stack if required. For

details of the 5V power connector see the section J2 – Power connector (5V option)

page 70

. Contact Eurotech Sales (see page 125) for details.

If a CompactFlash and an LCD display are used, ensure the total current

requirement on the 3.3V rail does not exceed 900mA. Please check the

datasheets of the devices you are using.